The present invention relates to a method for determining the optimal muscle length in a detached skeletal muscle.
Surgical reattachment of a detached muscle to a selected anatomical site is an important procedure in human and veterinary orthopaedic surgery. Surgical reattachment of a muscle may be required in cases of severe muscle injury, where an injured muscle must be removed, and the movement controlled by the injured muscle is to be partially restored by repositioning a healthy muscle. A muscle reattachment operation may also be required in the course of treatment of certain neuromuscular diseases, which are characterized by severe muscular contraction. One method of treatment is to detach the contracted muscle or muscles temporarily, followed by a later surgical reattachment.
It is important in a muscle reattachment operation to place the detached muscle at an optimal length with respect to the positions of the skeletal attachment members. This is because skeletal muscles have an inherent optimal length, with respect to the positions of the controlled skeletal members, which allows for optimal force-generation and functional range of the muscles. This optimal length is one in which the muscles are only slightly stretched when the skeletal members are in a neutral position, i.e., the approximate position assumed by the skeletal members in the middle of their total range of motion. At either a suboptimal length, where the muscle is in a relatively slack condition, or at an overly stretched condition, the muscular strength and functional range is significantly reduced.
From the foregoing, the importance of surgically reattaching a detached muscle at an optimal muscle length can be appreciated. Heretofore, orthopaedic surgeons have relied upon "feel" to determine when a muscle is at an optimal length, such occurring when the muscle is stretched just beyond a slack condition. This approach is not always satisfactory due to a number of factors which can mislead the surgeon. In particular, since the muscle being reattached is composed both of elastic connective tissue and contractile muscle components, both the elasticity of the connective tissue and tension of the muscle components will contribute to the overall muscle tension which is sensed. Because of the elasticity of the connective tissue, the muscle may be stretched too tight by the time the surgeon begins to feel tension. The amount of overstretching is typically one-half inch or more beyond optimal length.
It is a general object of the invention, therefore, to provide a simple and accurate method for determining optimal muscle length in a surgical operation involving reattachment of a detached striated muscle.
It is yet another object of the invention to provide such a method which uses reliable and relatively inexpensive components.